1. Technical Field
This invention generally relates to a word alignment apparatus, example sentence bilingual dictionary, word alignment method, and program product for word alignment.
2. Related Art
Machine translation is to convert from one language into another with the use of a computing machine. The research and development of the machine translation has been carried out around the glove over half a century. The machine translation system can be broadly categorized into (1) analysis-based machine translation, (2) example-based machine translation, and (3) statistics-based machine translation.
The analysis-based machine translation is a technique of analyzing a first language (morphologic analysis, syntactic and semantic analysis, and the like), converting an analysis result into a second language, and generating a translation sentence in the second language. Since the performance of analysis technique of a natural language is not good, it has limitations that to develop a good performance analysis-based machine translation system is very difficult. In addition, there are drawbacks in that learning is impossible, and thereby it is difficult to improve a translation engine.
The statistics-based machine translation is a technique of building a translation model with the use of a language model and a statistics model. In this method, realization is limited, because learning data (corpus) necessary for construction of each model is limited.
The example sentence-based machine translation imitates a mechanism how the human leans a foreign language, and translates a new document with reference to a translated example sentence that has been learned. In 1980s, Professor Nagao proposed this translation system for the first time. Since then, the research and development of the example-based machine translation have been increased.